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Check Engine Light
The check engine light comes on in a car when the engine is experiencing a problem. Ask questions here about your car's check engine light.
7,238 Questions
How do you reset the Service Engine Soon light on a 1998 Ford Taurus?
Disconnect the battery for 5 minutes.
Unhook the negative battery cable for a couple of minutes then reconnect it. It will clear all codes until the problem reoccurs when you start the engine.
Pull the codes from the computer, match the code to the troubleshooting procedure, follow the procedure to find the source. Repair the source, light will go out if that was the only problem. There are "monitors" or self tests the computer runs the car through a drive cycle, if a problem occurs, it may not run all of the self tests until that problem is taken care. Therefore, another problem may exist. It is emission related. OR hook up a scanner that is capable of clearing codes, and hope that none are still active.
The " check engine light" is by far one of the most misunderstood technological advances by the public. This is an needed in-depth understanding for the public. It is a warning light that is illuminated when there is a problem affecting the EMISSION SYSTEM only. Emission system being the pollution control system. Don't get a hard on against it as it is a good thing once you understand it. One point that was brought up a a recent meeting of technicians was that the amount of hydrocarbons is greater when the gas cap is left off than when the engine is running. Hydrocarbons are part of pollution emitted as gasoline evaporates. Going a step farther, one facet of the emission system is the "Evaporative" portion. This is when the fumes from the gasoline are leaking from the system into the outside air. This is one part of the emission system that can trigger a check engine light. I would say that about 7% of the vehicles that have a check engine light are the result of a loose or inadequate gas cap. But understand that many scenarios are possible with the "check engine light" The vehicle's powertrain computer (note that some vehicles have 17 different computers) will run a series of self-tests. They will only run under certain criteria. And they can be vastly different from manufacturer to manufacturer. Some self-tests are not run until preceding ones have run successfully. So if there is a problem in one particular area that is preventing another self test from running, you can have a situation where one problem is fixed, but another still exists. If you fix a problem and drive the car through a drive cycle that sets the monitor (or self test) the light will go off as it passes that criteria that triggered it in the first place. After 1996, the auto industry went to a idea called OBD II (on board diagnostics). This was to get all the manufacturers onto a similar plane for troubleshooting and powertrain control. While they still differ vastly, many corrections and adaptations were made for technicians to better fix the check engine light problems. Prior to this there were so many different and poor troubleshooting data from a check engine light problem that resolving the problem was much more difficult. Many early warning light of this nature were set to illuminate based on mileage. An Oxygen sensor was one of the things that were meant to be replaced when that mileage was hit. This is much like many current "Change oil lights� that are set based on a pre-set mileage.
1996 Mercury Villager the check engine light comes on and off?
have vehicle scanned to determine problem
What did the check engine light codes say was bad?
2004 Ford Freestar check engine light flashes and then stays on?
Your vehicle is trying to tell you that there is a problem that needs attention. If you do not have a reader to check your own codes, then you should take your vehicle to a mechanic to have it looked at. Ignoring the issue can potentially cause more issues that could be more costly.
Your alero 2001 shifting hard check engine light on has a trouble code p1111 po 113 HOW CAN I FIT?
I just came in from the cold, fixing the same problem you are talking about (P0113). My 3.4L V6 01 Alero was hard shifting with the Service Engine light on. The Diagnostic Trouble Code was P0113: Intake Air Temperature Circut, High Input. The Trouble Code P1111 is a similar problem: Intake Air Temperature sensor circut intermittent high voltage. Hoping for the easy fix I bought and installed a new IAT sensor (AKA: Air Charge Sensor) at AutoZone for $13.99, but it didn't help anything.
The problem was the wiring leading to the sensor had broken. The IAT sensor shares the same 5V reference voltage with the Coolant Sensor and the Throttle Position Sensor. When the wire broke at the IAT Sensor, the TPS signal got messed up telling the computer to up the transmission pressure to "protect" the transmission. (Even though it felt like it was destroying the transmission shifting that hard)
The solution to the problem was to order a new IAT Sensor connector pigtail, GM Part #12102620/ AC Delco Part #PT307/ PICO Part #5616. I found mine at bmotorsports.com for under $8.00 after shipping. Stagger your cuts on the pigtail wires, heat shrink both butt connectors, and re-apply some electrical tape and you'll be back to smooth shifting in no-time!
What to do if your Check engine light stays on on 2004 Dodge Grand Caravan?
go to autozone to ask to check your codes
Why does check engine light blink on my 5.7 liter vortec 97 Chevy taho?
A flashing "check engine" light indicates that you're having a serious problem with one or more of the EFI circuits. You need to connect it to a diagnostic code reader to find out what's wrong. I suggest a visit to your local auto parts retailer where you can usually borrow, rent or buy a code scanner that will work with your vehicle.
When it's flashing there is often a potential that something serious is going on that can even cause permanent damage to the engine.
Will your car pass the mot with the tcs light on all the time?
Yes, the Traction Control System (TCS) light has nothing to do with emissions.
Your 2002 acura tl type-s has a check engine and a vsa light on whats wrong with it?
I have the same problem.... I had a friend that put it on a computer (they only cost around $50) and it told me that I had misfires in 5 of the cylinders which means I need a tune up.... Once I get the tune up I will let you know if they come back. i just replaced my trans on my acura tl type s , and what ur saying is exactly what happ to me my vsa light came on then my check engine light then my car was acting crazy n i needed a turq converter my transmission filter was clogging cause my 3rd gear was breaking down
Why do your Cougar XR7 headlights come on when engine is turned on?
the vehicle is equipped with daytime running lights a safety feature that most vehicles have not alot can be done unless you want to tear the drivers dash apart to take the sensor out that is located near the vin plate in the dash
YOUR MOM
What does it mean when the service engine soon comes on for your 1999 gmc Yukon?
The check engine light (service engine soon) comes on and stays on when a problem is detected by the self diagnosis system of your vehicle. Generally, the problem is in the emissions or something that is affecting the effectiveness of the emissions, but other causes can trigger the light to come on, too. To determine the cause, the vehicle will need to be taken to a parts store or a shop that has an OBD2 scanner, or for 1995 and earlier models, an OBD1 scanner, While a scanner will not give you the magic answer, it will give you a code that narrows down the problem area.
2001 b3000 misfire and low compression cylinder 4 why?
A misfire and low compression on the same cylinder are indications of an internal engine problem. You need to do a cylinder leakage test. That is where you set cylinder at top dead center with the valves closed and apply air pressure down the plug hole and see where it leaks out. If it leaks out the exhaust pipe the exhaust valve is bad etc.... If you haven't performed this particular maneuver before, and don't know the potential problems, you need to be VERY careful. When you add compressed air the engine will turn and if you have anything resting on the serpentine belt or any other moving part, it could get caught and cause damage. Low compression can also be the result of "blow-by" (caused by worn or sticking rings) or by a leaking head gasket (caused by a warped head when the engine overheated).
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How do you check a bit is on or off?
To determine if a specific bit within a bitset is on or off, use the bitwise AND operator. Note that a bitwise AND is not the same as a logical AND.
Logical AND (or &&) is used in Boolean logic:
x && y is true when x and y are both true, otherwise it is false.
Bitwise AND (or &) compares each corresponding bit, returning a value that indicates which bits are set in both values. This is best seen when the two values are placed one above the other so we can compare the corresponding bits:
10101100 &
10110101 =
10100100
From this we can see that the 3rd, 6th and 8th bits are set in both values.
Knowing this, we can determine the state of any individual bit in any value by simply bitwise ANDing the value with the specific bit we are looking for. If the result is zero, then the bit is not set but if the result is nonzero, then it is set.
As an example, let us suppose we want to test if bit 4 is set. Note that bit 4 is not the same as saying the 4th bit. Bit 4 is actually the 5th bit because bit 0 is always the least significant bit in binary. The reason is that bit 0 represents 2 raised to the 0th power which is 1 in decimal or 00000001 in binary. Bit 4 therefore means 2 raised to the 4th power which is 16 decimal or 00010000 in binary.
In decimal notation, we can determine if bit 4 is set in variable named x like so:
x = 181;
if ((x & 16) == 0)
{
// bit 4 is not set
}
else
{
// bit 4 is set
}
Normally it is easier to use hexadecimal notation as it makes it more obvious we are performing a bitwise operation upon binary values rather than decimal values (which is notationally confusing). Given that 16 is 0x10 in hexadecimal, we then get:
x = B5;
if ((x & 0x10) == 0)
{
// bit 4 is not set
}
else
{
// bit 4 is set
}
Note that ((x & 0x10) == 0) is the same as saying (!(x & 0x10)) while ((x & 0x10) != 0) is the same as saying (x & 0x10). The latter is notationally simpler, thus it often makes more sense to reverse the logic:
x = 0xB5;
if (x & 0x10) // read as: if (x & 0x10) is nonzero
{
// bit 4 is set
}
else
{
// bit 4 is not set
}
If we suppose that x is 0xB5 (181 decimal), then we can see more clearly how this works by examining the binary notation:
0xB5 : 10110101 &
0x10 : 00010000 =
0x10 : 00010000 (non-zero, so bit 4 is set)
If we now suppose that x is 0xA5 (165 decimal), then we get:
0xA5 : 10100101 &
0x10 : 00010000 =
0x00 : 00000000 (zero, so bit 4 is not set)
Note that when we're only checking for one bit and that bit is set, the return value is always the same value as the bit we are actually checking for. But when we check for more than one bit (as per the original example at the top of this answer), the result is either zero (none of the bits are set), or some combination of the bits we were looking for (one or more of the bits are set). Therefore it's easier to say the result is either zero or non-zero regardless of how many bits we're checking for.
Another notation we often encounter is the following:
x = 0xB5;
if (x & (1<<4))
{
// bit 4 is set
}
else
{
// bit 4 is not set
}
It looks more complex at first, but it is actually more readable than the hexadecimal notation. 1<<4 is a bit-shift left operation that shifts a 1 four bits to the left (>> would shift to the right). 1 in binary is 00000001, thus if we shift left 4 times we get 00010000. Thus 1<<4 is effectively the same as saying bit 4. By the same token, 1<<7 would mean bit 7 while 1<<2 would mean bit 2. Expressing ideas directly in code like this means we don't need to comment our code so much; it becomes self-documenting.
Note that bit-shifting like this only works when we're only interested in a single bit. However, knowing that we can shift bits left or right means we can more easily determine the status of every bit using a simple for loop:
x = 0xB5;
for (i=0; i<8; ++i) // assumes x is an 8-bit value
{
if (x & (1< { // bit i is set } else { // bit i is not set } } If we want to output the individual bits to a character stream such as standard output, we need to work in reverse, starting from bit 7: x = 0xB5; b = 1<<7; // bit 7 while (b) { if (x & b) { std::cout << '1'; // note: << means 'insert' in this context } else { std::cout << '0'; } b = b>>1; // bit-shift right } std::cout << std::endl; Note that languages like C++ allow the same operator to perform different operations depending on the context. Hence << can be used to bit-shift a value or to insert a character into a character stream. Re-using symbols according to their context like this helps keep the number of symbols to a minimum. C++ also allows us to write the same code in a more concise form: x = 0xB5; b = 1<<7; while (b) { std::cout << (x & b ? '1' : '0'); b = b>>1; } std::cout << std::endl; Of course, there is an even easier way to print an 8-bit binary value in C++: x = 0xB5; std::bitset<8> b (x); std::cout << b << std::endl;
A flashing service light (called a MIL or malfunction indicator lamp) indicates misfiring has been detected. DO NOT DRIVE THE CAR $$$$$. Get the misfiring repaired, could be bad coil or coil packs, bad wires, bad plugs. Driving with misfire can destroy the catalytic converter.
Is there a trick to turn off the service engine soon light on a 99 Saturn Sc-1?
For most Saturns there is a button inside the under-hood fuse panel. With the key on and the engine off, press the button for 15 seconds and it should clear the code... I think. I have to refer to the manual whenever I do that so you may have to do the same.
How do you disable the check engine chime on my 2008 pt cruiser?
The chime can not be disabled or removed.
How do you reset the service engine light on a 2002 GMC Envoy after repair?
Stepping 3 times on the accelerator pedal while in 'run" mode will reset the "Oil Change Light" but not the "Check Engine Light". Still looking for the answer...!
AnswerMost of the OBD2 code scanners have the ability to clear a code. You can usually borrow, rent or buy an OBD2 code scanner from most auto parts retailers. AnswerWell I don't know if this will work on this model but this worked on similar full-sized trucks of the same time frame. Turn the key to run but do not start engine. While in "run" mode step on the accelerator pedel (3)three times then start engine. Couldn't hurt to try it. R.W.if its ses light remove battery ground cable for 30se.
ETS means ENHANCED TRACTION SYSTEM. You need to have the ECU scanned and see what codes come up. With these codes an expert can diagnose the cause of the problem.
Check engine code 1990 Mazda 323?
1990 Mazda 323:The check engine light intermittently flashes a series of long and short intervals. A long flash is followed by 5 short flashes. Then another long flash is followed by 7 short flashes, a pause, and 9 more short flashes. How should I interpret this code?
